I think that one of the problems regarding the promotion of the hobby could be the attitude of some clubs and long time participants in this hobby. I've been flying RC for decades but for a long while I worked away from home and never knew how much time I would have in one place to join a club, though I have been a member of the AMA. Several years ago I landed a position with a consulting company close to home and thought that I would like to join a local club, mainly to meet some fellow fliers and have a place to fly larger aircraft. There are two clubs in my area, one 40 miles away, another within 10 miles of my house. I contacted them both about membership. One gave me their meeting place and time and invited me to come to a meeting, and oh by the way be sure to bring my dues money if I wanted to fly. The other, the one further away invited me to a meeting to meet the other members and oh by the way, bring a plane to fly, whether you decide to join or not! Guess which club I am a member of. If there had only been the closer club with the attitude I received as a potential member I wouldn't be in a club at all.
I have flown at AMA club fields as a guest in areas where I was staying for work away from home and always donated something or at least offered to.
Some of the long time participants in this hobby are less than welcoming, I don't think it is the majority but it isn't far less than half in my experience.